package org.github.rayson517.easyplatform.common.web.util;

import java.awt.image.BufferedImage;
import java.io.IOException;
import java.io.OutputStream;
import java.util.Hashtable;

import javax.imageio.ImageIO;

import com.google.zxing.BarcodeFormat;
import com.google.zxing.EncodeHintType;
import com.google.zxing.MultiFormatWriter;
import com.google.zxing.WriterException;
import com.google.zxing.common.BitMatrix;

/**
 * 
 * <p>Title: QRCodeUtil</p>
 * <p>Description: 二维码生成工具类</p>
 * @author rayson517
 * @date 2018-03-06 17:34
 * @version 1.0
 */
public class QRCodeUtil {
    /**
     * 黑色
     */
    private static final int BLACK = 0xFF000000;
    
    /**
     * 白色
     */
    private static final int WHITE = 0xFFFFFFFF;
    
    /**
     * 将二维码生成 并以IO流的方式输出到网页上
     * @param website 二维码数据
     * @param output 输出流
     * @throws WriterException 写入异常
     * @throws IOException IO异常
     */
    public static void genGR(String website, OutputStream output) throws WriterException, IOException {
        int width = 300;
        int height = 300;
        String format = "jpg";
        Hashtable<EncodeHintType, String> hints = new Hashtable<EncodeHintType, String>();
        hints.put(EncodeHintType.CHARACTER_SET, "utf-8");
        BitMatrix bm = new MultiFormatWriter().encode(website, BarcodeFormat.QR_CODE, width, height, hints);
         
        BufferedImage image = toImage(bm);
        ImageIO.write(image, format, output);   //把二维码写到response的输出流
    }
    
    /**
     * 生成二维码图片
     * @param bm
     * @return
     */
    private static BufferedImage toImage(BitMatrix bm) {
        int width = bm.getWidth();
        int height = bm.getHeight();
        BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
        for(int x = 0;x < width; x++){
            for(int y = 0; y < height; y++ ){
                image.setRGB(x, y, bm.get(x, y) ? BLACK : WHITE);
            }
        }
        return image;
    }
}
